Fault Phenomenon: Zoomlion ZR220 rotary drilling rig during feed or lifting, the mast shakes, Kelly bar rubs against mast.

Troubleshooting Process:
– Checked wear pads: guide pads worn down.
– Checked guide rails: mast guide rails worn with step.
– Checked clearance: excessive clearance between pad and rail.
– Checked lubrication: lack of grease.

Root Cause: The Kelly bar guide wear pads on the mast were not replaced after long-term wear, causing excessive clearance and unstable Kelly bar operation.

Required Parts: Replace all guide wear pads, repair guide rails.